Construction and Potential Applications of Biosensors for Proteins in Clinical Laboratory Diagnosis

MicroRNA biosensors for the detection of liver cancer

Liver cancer is one of the deadliest types worldwide and early diagnosis is highly important for successful treatment. Therefore, it is necessary to develop rapid, sensitive, simple, and inexpensive analytical tools for its detection. MicroRNAs (miRNA) represent unique biomarkers whose expression in biofluids is strongly associated with cancer in general and miR-21, -31, -122, -145, -146a, -200c, -221, -222, and -223 in liver cancer, specifically. Various biosensors for miRNA detection have been developed. These include electrochemical biosensors based on amperometric, potentiometric, conductometric and impedimetric technology. Furthermore, the use of advanced nanomaterials with enhanced chemical stability, conductivity and electrocatalytic activity have greatly increased the sensitivity and specificity of these devices. The present review focuses on recent advances in electrochemical biosensors for miRNA detection in liver cancer.

Immunosensors for Autoimmune-Disease-Related Biomarkers: A Literature Review

Immunosensors are a special class of biosensors that employ specific antibodies for biorecognition of the target analyte. Immunosensors that target disease biomarkers may be exploited as tools for disease diagnosis and/or follow-up, offering several advantages over conventional analytical techniques, such as rapid and easy analysis of patients' samples at the point-of-care. Autoimmune diseases have been increasingly prevalent worldwide in recent years, while the COVID-19 pandemic has also been associated with autoimmunity. Consequently, demand for tools enabling the early and reliable diagnosis of autoimmune diseases is expected to increase in the near future. To this end, interest in immunosensors targeting autoimmune disease biomarkers, mainly, various autoantibodies and specific pro-inflammatory proteins (e.g., specific cytokines), has been rekindled. This review article presents most of the immunosensors proposed to date as potential tools for the diagnosis of various autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. The signal transduction and the immunoassay principles of each immunosensor have been suitably classified and are briefly presented along with certain sensor elements, e.g., special nano-sized materials used in the construction of the immunosensing surface. The main concluding remarks are presented and future perspectives of the field are also briefly discussed.

2D carbon materials based photoelectrochemical biosensors for detection of cancer antigens

Cancer is a leading cause of death globally and early diagnosis is of paramount importance for identifying appropriate treatment pathways to improve cancer patient survival. However, conventional methods for cancer detection such as biopsy, CT scan, magnetic resonance imaging, endoscopy, X-ray and ultrasound are limited and not efficient for early cancer detection. Advancements in molecular technology have enabled the identification of various cancer biomarkers for diagnosis and prognosis of the deadly disease. The detection of these biomarkers can be done by biosensors. Biosensors are less time consuming compared to conventional methods and has the potential to detect cancer at an earlier stage. Compared to conventional biosensors, photoelectrochemical (PEC) biosensors have improved selectivity and sensitivity and is a suitable tool for detecting cancer agents. Recently, 2D carbon materials have gained interest as a PEC sensing platform due to their high surface area and ease of surface modifications for improved electrical transfer and attachment of biorecognition elements. This review will focus on the development of 2D carbon nanomaterials as electrode platform in PEC biosensors for the detection of cancer biomarkers. The working principles, biorecognition strategies and key parameters that influence the performance of the biosensors will be critically discussed. In addition, the potential application of PEC biosensor in clinical settings will also be explored, providing insights into the future perspective and challenges of exploiting PEC biosensors for cancer diagnosis.

Electrochemical biosensors based on peptide-kinase interactions at the kinase docking site

Kinases are important cancer biomarkers and are conventionally detected based on their catalytic activity. Kinases regulate cellular activities by phosphorylation of motif-specific multiple substrate proteins, resulting in a lack of selectivity of activity-based kinase biosensors. We present an alternative approach of sensing kinases based on the interactions of their allosteric docking sites with a specific partner protein. The new approach was demonstrated for the ERK2 kinase and its substrate ELK-1. A peptide derived from ELK-1 was bound to a gold electrode and ERK2 sensing was performed by electrochemical impedance spectroscopy. We performed a detailed analysis of the interaction between the ELK-1 peptide and the kinase on gold surfaces. Atomic force microscopy, variable angle spectroscopic ellipsometry, X-ray Photoelectron Spectroscopy, and polarization modulation IR reflection-absorption spectroscopy analysis of the gold surface revealed the adsorbed layer of the ERK2 on the peptide monolayer. The sensors showed a high level of target selectivity for ERK2 compared to the p38γ kinase and BSA. ERK2 was detected in its cellular concentration range, 0.5-2.0 μM, and the limit of detection was calculated to be 0.35 μM. Using the flexibility of peptide design, our method is generic for developing sensitive and substrate-specific biosensors and other disease-related enzymes based on their interactions.

Veni, Vidi, Vici: Immobilized Peptide-Based Conjugates as Tools for Capture, Analysis, and Transformation

Analysis of peptide biomarkers of pathological states of the organism is often a serious challenge, due to a very complex composition of the cell and insufficient sensitivity of the current analytical methods (including mass spectrometry). One of the possible ways to overcome this problem is sample enrichment by capturing the selected components using a specific solid support. Another option is increasing the detectability of the desired compound by its selective tagging. Appropriately modified and immobilized peptides can be used for these purposes. In addition, they find application in studying the specificity and activity of proteolytic enzymes. Immobilized heterocyclic peptide conjugates may serve as metal ligands, to form complexes used as catalysts or analytical markers. In this review, we describe various applications of immobilized peptides, including selective capturing of cysteine-containing peptides, tagging of the carbonyl compounds to increase the sensitivity of their detection, enrichment of biological samples in deoxyfructosylated peptides, and fishing out of tyrosine–containing peptides by the formation of azo bond. Moreover, the use of the one-bead-one-compound peptide library for the analysis of substrate specificity and activity of caspases is described. Furthermore, the evolution of immobilization from the solid support used in peptide synthesis to nanocarriers is presented. Taken together, the examples presented here demonstrate immobilized peptides as a multifunctional tool, which can be successfully used to solve multiple analytical problems.

Industry 4.0 Technologies for the Manufacturing and Distribution of COVID-19 Vaccines

BACKGROUND

The evolutionary stages of manufacturing have led us to conceptualize the use of Industry 4.0 for COVID-19 (coronavirus disease 2019), powered by Industry 4.0 technologies. Using applications of integrated process optimizations reliant on digitized data, we propose novel intelligent networks along the vaccine value chain. Vaccine 4.0 may enable maintenance processes, streamline logistics, and enable optimal production of COVID-19 vaccines.

VACCINE 4.0 FRAMEWORK

The challenge in applying Vaccine 4.0 includes the requirement of large-scale technologies for digitally transforming manufacturing, producing, rolling-out, and distributing vaccines. With our framework, Vaccine 4.0 analytics will target process performance, process development, process stability, compliance, quality assessment, and optimized maintenance. The benefits of digitization during and post the COVID-19 pandemic include first, the continual assurance of process control, and second, the efficacy of big-data analytics in streamlining set parameter limits. Digitization including big data-analytics may potentially improve the quality of large-scale vaccine production, profitability, and manufacturing processes. The path to Vaccine 4.0 will enhance vaccine quality, improve efficacy, and compliance with data-regulated requirements.

DISCUSSION

Fiscal and logistical barriers are prevalent across resource-limited countries worldwide. The Vaccine 4.0 framework accounts for expected barriers of manufacturing and equitably distributing COVID-19 vaccines. With amalgamating big data analytics and biometrics, we enable the identification of vulnerable populations who are at higher risk of disease transmission. Artificial intelligence powered sensors and robotics support thermostable vaccine distribution in limited capacity regions, globally. Biosensors isolate COVID-19 vaccinations with low or limited efficacy. Finally, Vaccine 4.0 blockchain systems address low- and middle-income countries with limited distribution capacities.

CONCLUSION

Vaccine 4.0 is a viable framework to optimize manufacturing of vaccines during and post the COVID-19 pandemic.

1.0 V-0.18 µm CMOS Tunable Low Pass Filters with 73 dB DR for On-Chip Sensing Acquisition Systems

This paper presents a new approach based on the use of a Current Steering (CS) technique for the design of fully integrated Gm–C Low Pass Filters (LPF) with sub-Hz to kHz tunable cut-off frequencies and an enhanced power-area-dynamic range trade-off. The proposed approach has been experimentally validated by two different first-order single-ended LPFs designed in a 0.18 µm CMOS technology powered by a 1.0 V single supply: a folded-OTA based LPF and a mirrored-OTA based LPF. The first one exhibits a constant power consumption of 180 nW at 100 nA bias current with an active area of 0.00135 mm2 and a tunable cutoff frequency that spans over 4 orders of magnitude (~100 mHz–152 Hz @ CL = 50 pF) preserving dynamic figures greater than 78 dB. The second one exhibits a power consumption of 1.75 µW at 500 nA with an active area of 0.0137 mm2 and a tunable cutoff frequency that spans over 5 orders of magnitude (~80 mHz–~1.2 kHz @ CL = 50 pF) preserving a dynamic range greater than 73 dB. Compared with previously reported filters, this proposal is a competitive solution while satisfying the low-voltage low-power on-chip constraints, becoming a preferable choice for general-purpose reconfigurable front-end sensor interfaces.

Rapid detection of SARS-CoV-2 antibodies using electrochemical impedance-based detector

Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was classified as a pandemic by the World Health Organization and has caused over 550,000 deaths worldwide as of July 2020. Accurate and scalable point-of-care devices would increase screening, diagnosis, and monitoring of COVID-19 patients. Here, we demonstrate rapid label-free electrochemical detection of SARS-CoV-2 antibodies using a commercially available impedance sensing platform. A 16-well plate containing sensing electrodes was pre-coated with receptor binding domain (RBD) of SARS-CoV-2 spike protein, and subsequently tested with samples of anti-SARS-CoV-2 monoclonal antibody CR3022 (0.1 μg/ml, 1.0 μg/ml, 10 μg/ml). Subsequent blinded testing was performed on six serum specimens taken from COVID-19 and non-COVID-19 patients (1:100 dilution factor). The platform was able to differentiate spikes in impedance measurements from a negative control (1% milk solution) for all CR3022 samples. Further, successful differentiation and detection of all positive clinical samples from negative control was achieved. Measured impedance values were consistent when compared to standard ELISA test results showing a strong correlation between them (R2=0.9). Detection occurs in less than five minutes and the well-based platform provides a simplified and familiar testing interface that can be readily adaptable for use in clinical settings.

Early Diagnosis of Multiple Sclerosis Based on Optical and Electrochemical Biosensors: Comprehensive Perspective

Background:

Multiple Sclerosis (MS) involves an immune-mediated response in which body’s immune system destructs the protective sheath (myelin). Part of the known MS biomarkers are discovered in cerebrospinal fluid like oligoclonal lgG (OCGB), and also in blood like myelin Oligodendrocyte Glycoprotein (MOG). The conventional MS diagnostic methods often fail to detect the disease in early stages such as Clinically Isolated Syndrome (CIS), which considered as a concerning issue since CIS highlighted as a prognostic factor of MS development in most cases.

Methods:

MS diagnostic techniques include Magnetic Resonance Imaging (MRI) of the brain and spinal cord, lumbar puncture (or spinal tap) that evaluate cerebrospinal fluid, evoked potential testing revealing abnormalities in the brain and spinal cord. These conventional diagnostic methods have some negative points such as extensive processing time as well as restriction in the quantity of samples that can be analyzed concurrently. Scientists have focused on developing the detection methods especially early detection which belongs to ultra-sensitive, non-invasive and needed for the Point of Care (POC) diagnosis because the situation was complicated by false positive or negative results.

Results:

As a result, biosensors are utilized and investigated since they could be ultra-sensitive to specific compounds, cost effective devices, body-friendly and easy to implement. In addition, it has been proved that the biosensors on physiological fluids (blood, serum, urine, saliva, milk etc.) have quick response in a non-invasive rout. In general form, a biosensor system for diagnosis and early detection process usually involves; biomarker (target molecule), bio receptor (recognition element) and compatible bio transducer.

Conclusion:

Studies underlined that early treatment of patients with high possibility of MS can be advantageous by postponing further abnormalities on MRI and subsequent attacks.

:

This Review highlights variable disease diagnosis approaches such as Surface Plasmon Resonance (SPR), electrochemical biosensors, Microarrays and microbeads based Microarrays, which are considered as promising methods for detection and early detection of MS.

A CMOS Low Pass Filter for SoC Lock-in-Based Measurement Devices

This paper presents a fully integrated G_m–C low pass filter (LPF) based on a current steering G_m reduction-tuning technique, specifically designed to operate as the output stage of a SoC lock-in amplifier. To validate this proposal, a first-order and a second-order single-ended topology were integrated into a 1.8 V to 0.18 µm CMOS (Complementary Metal-Oxide-Semiconductor) process, showing experimentally a tuneable cutoff frequency that spanned five orders of magnitude, from tens of mHz to kHz, with a constant current consumption (below 3 µA/pole), compact size (<0.0140 mm²/pole), and a dynamic range better than 70 dB. Compared to state-of-the-art solutions, the proposed approach exhibited very competitive performances while simultaneously fully satisfying the demanding requirements of on-chip portable measurement systems in terms of highly efficient area and power. This is of special relevance, taking into account the current trend towards multichannel instruments to process sensor arrays, as the total area and power consumption will be proportional to the number of channels.

Impact of Molybdenum Compounds as Anticancer Agents

The aim of this mini review was to report the molybdenum compound intervention to control cancer disease. The intervention explains its roles and progress from inorganic molybdenum compounds via organomolybdenum complexes to its nanoparticles to control oesophageal cancer and breast cancer as case studies. Main contributions of molybdenum compounds as anticancer agents could be observed in their nanofibrous support with suitable physicochemical properties, combination therapy, and biosensors (biomarkers). Recent areas in anticancer drug design, which entail the uses of selected targets, were also surveyed and proposed.

A 0.18 μm CMOS LDO Regulator for an On-Chip Sensor Array Impedance Measurement System

This paper presents a fully integrated 0.18 μm CMOS Low-Dropout (LDO) Voltage Regulator specifically designed to meet the stringent requirements of a battery-operated impedance spectrometry multichannel CMOS micro-instrument. The proposed LDO provides a regulated 1.8 V voltage from a 3.6 V to 1.94 V battery voltage over a −40 °C to 100 °C temperature range, with a compact topology (<0.10 mm² area) and a constant quiescent current of only 7.45 μA with 99.985% current efficiency, achieving remarkable state-of-art Figures of Merit (FoMs) for the regulating–transient performance. Experimental measurements validate its suitability for the target application, paving the way towards the future achievement of a truly portable System on Chip (SoC) platform for impedance sensors.